Air-heating furnace



April 22, 1930.

R. E. CRAMER l 1,755,727

AIR HEATING FURNACE Filed Nov. l5, 1928 2 Sheets-Sheet 2 Invenor:

xand upwardly inclinV Patented Apr. 2 2, 1930 UNITED sf1jATEs IParaNT orner;v

A1B-HEATING FUnNAcE Appncamn'niea Nuvember 1s, 192s. serial No. 319,121.

.' This invention relates to air heating furnaces and, 'while not limited thereto, relates more particularly to domestichot air furnaces, 'and has for its object the provision of a gwardly extending vertical portion 13 which 5 furnace of this class having a fuelburner of the radiant type andv adapted for use with gaseous, liquid or solid fuel.

Another object is to-provide a furnace i'n which the air to be heated is subjected to both lilradiant heatand heat by .convection from the walls of a heating chamber.

A further object is to provide a novel furnace construction in which the heated gases 'or products of combustion will flow countercurrent to the flow of air to be heated.

In the drawings: A Figure l'is a vertical sectional Aelevation through a hot air furnace constructed in accordance with this invention. 2 Figure 2 is a transverse sectional view tal'en on the line II--II of Figure 1.

vention.

Referring more particularly to the drawl v annular wall 7 is spaced inwardly from said casing or shell 2 and extends upwardly from vadjacent the lower end of said casing 1n parallel relation with said casing to apoint sub-- 7 stantially midway of the ends of said casing, 4 1 and is then inclined'inwardly and upwardly,

as at 9, and terminates at a point materially below the. upper end of the casing 2.v The second annular wall 8, which is spacedinwardly vfrom the wall 7, extends upwardly "I 45 andinwardly on a slight angle for a distance substantially equal to the length of the wall 7 which parallels the casing 2 and then is' inclined inwardly and upwardly parallel for a distance substantially equal to the inwardly portion 9 ofthe wall re 3 is a view similar to Figure 1," showmga slightly modilied form of the in- 7, as at 10. The wall 8 then extends verti cally to a point short of t-he to 3 of the casing 2, as at 12, and is reversely ent outwardly anddownwardly to form a spaced downengages and is secured to the upper face of the inclined portion 9 of the wall 7. The reversely bent andparallel portions 12 yand 13, effect, form a combustion zone or chamber -1n the heating chamber 6, and an annular fuel burner of the radiant type 15 is mounted on the upper end of the portion 9 of the wall 7 and 1s adapted toradiate heat through the upper portion of the walls 7 and 8 and the hot gases and products of combustion are iadaptedl to lowl downwardly through the chamber 6 and heat the air on the outside of the walls 7 and 8 by convection. The lower end of the chamber 6 is closed bya. wall 16 connecting the walls 7 and 8. y

Av iue 17 is in communication with 'the lower end of the chamber 6 throu h which l the products of combustion are a apted to pass and vertical balilewalls 18 are provided in the chamber 6 to prevent cross-flow or short-circuiting of the heated gasesand products of combustion before they travel tothe bottom of the chamber.

The space between the outer wall 7 of the chamber 6 and the casing 2 forms a hot air.

chamber 19 through which air to be heated is adapted to ow upwardly from thelower end to the hot air conduits 4 in the top 3 of the casing.

The radiant type of burner 15 is adapted.

to heat the air by jdirect radiation to the portion of heating chamber wall .13, while the air is preheated prior to reaching this lpoint by convection from the hot gases and products of combustion passing downwardly through the' chamber 6. In order to in crease the radiating surface of the wall portion 13 in contact with the air beingheated, this portion of wall is rovided with a-plurality of radiating fins 2 which extend into the l'path 'of travel of the air in the chamber 19. Suitable changes will be made when a solid or liquid fuel is employed, as will readily be understood. j

A choke shell or filler member 21 is mounted centrally within the space surrounded by the wall 8 and is spac from the wall 8 so as to provide an annu ar air space or cham- I ber 22 through which cold air may flow upwardly to the upper end of the shell 2 and befrom the furnace.

come heated by the heat transmitted by convection from theuheating chamber.

The lower portion of the wall 8, being inc'l'ined inwardly, provides a heating chamber 6 of decreasing cross-section toward the exit end so that the gradually cooling gases and Aproducts -of combustion as they contract will be forced into intimate contact with the walls 7 and 8.

In Figure 3 I have shown a slightly modilied form of my invention, in which a forced draft of air is drawn through and forced In this construction the top 3 of the casing 2 is provided with a manifold hot .air outlet 40 having a plurality of conduit outlets 40a.

A fan casing 41 is suspended from the top 3 and is in communication with the manifold outlet 40. A fan rotor 42 is mounted in the casing 41 and has its shaft 43 extending through the casing 2 and journaled in bearings 44. A motor bracket 45 is secured to the side of the casing 2 and supports a motor 46 which is coupled to the shaft 43.` The sides of the fan casing 41 are cut away adjacent each end of the fan rotor so as to permit the fan to pull or draw the air to be heated through the furnace where it is heated before it is drawn through the fan and forced from the fan casing 41 through the manifold 40.

While I have shown and described certain specific embodiments of my invention as adapted for use with gaseous fuel, it will be understood that I do not wish to be limited thereto, since solid or liquid fuel may be used and various modifications in the construction and arrangementofpaths may be tending from adjacent the lower end of said casing upwardly to a point intermediate the ends of said casing and then inclined inwardly and upwardly and terminating at a point materially below the'upper end of said casing, a second annular wall spaced inwardly from said first named annular wall, said last named wall extending upwardly from appoint adjacent the lower end of said rst named annular wall to a polnt adjacent the inward- Y ly and upwardly inclined portion of said first named annular wall and then being inclined inwardly and upwardly in spaced parallel relationv to said inclined portion of said first named wall, .then extending vertically yupward above said rst named annular wall and then being reversely bent and extended vertically downward and in contact with the upper face of said inclined portion of said first named annular wall, a bottom wall closing the space between said first and second named annular walls so as to form a closed heating chamber, the space between said casing and said lirst-named annular wall and said casing and the upper end of said second named annular wall forming a hot air chamber for cold air adapted to enter at the lower end of said casing, a fuel burner in the upper end of said heating chamber above said iirst named annular wall, a flue communicating with the lowerend of said heating chamber, vertical baflles said heating chamber to prevent short-circuiting of the heated gases and products of combustion, and fins on the outer.

surface of the reversely bent portion of said second annular wall so as to increase the heated surface in contact with the air to be heated. 4

2. A hot air furnace comprising an outer casing composed of enclosing side and top walls, hot air conduits communicating with ing, a second annular wall spaced inwardly from said first named annular wall, said last named Wall extending upwardly from a point adjacent the lower end of said first named annular wall to a point adjacent the inwardy ly Land upwardly inclined port-ion of said first named annular wall and then being inclined inwardly and upwardly in spaced parallel. relation to said inclined portion of said first named wall,then extending yertically upward above said lirst named annular wall and then being reversely bent and ex-` tended vertically downward and in Contact with the upper face of said inclined portion of said first named annular wall, a bottom wall closing the space between said first and second named annular walls so as to form a closed heating chamber, the space between' said casing and said first named annular wall and said casing and the upper end of said second named annular wall forming a hot air chamber for cold air adapted to enter at the lower en d of said casing, a radiant type fuel burner in the upper end of said heat ing chamber above said first named annular wall,` a tlue communicating with the lower end of said heating chamber, vertical baies in said heating chamber to prevent shortcircuiting of the heated gases and products of co'mbustion, and ns on the outer surface casing upwardly to a point intermediate the ends of said casingand 'then .inclined inwardly andupwardly and terminating at a point materially below the u per end of said casing, a second annular wa spaced inwardly from said rst named annular wall, said last'named wall extending upwardly from a point ladjacent thelower end of said rst named annular wall to a `point adjacent the inwardly and upwardly'inclined portion of said first named annular wall and then bein inclined inwardly and upwardly in space parallel relation to said inclined portion of said first named wall, then extending vertically upward above said first named annular wall and then -being reversely bent and extended vertically downward and in contact with the upper face of said inclined portion of said first named annular wall, a bottom wall closing the space between said first and second named annular walls so as to form al closed heating chamber, the space between said casing and said first named annular wall and said casing and the upper end of said second named annular wall forming a hot air chamber for cold air adapted to enter at the lower end of said casing, a gaseous fuel burner in the upper end of said heating chamber above said first named annular wall, a flue communicating with the lower end of said heat- 'ing chamber, vertical baiies in said heating chamber to prevent short-circuiting of the heated gases and products of combustion, fins on the outer surface of the reversely bent portionof said second annular wall so as to increase the heated surface in contact with the air to vbe heated, and a choke shell spaced annularly from the inner face of said second named annular wall so as to form a limited passage for air to be heated along the inner wall of said heating chamber.

4. A hot air furnace comprising an outer hot air con uits communicating with the upper end of said casing, an annular wall spaced inwardly from said casing and extending from adjacent the lower end of said casing upwardly to a point intermediate the ends of said casing, a second annular wall spaced inwardly from' said first named annuwall closing the space between said first and second named walls so as to form a closed heating chamber, the space between said casing and said irstA named annular wall and said casing and the ufpper end of said second named annular wall orming a hot air chamber for cold air adapted to enter at the lower end of said casing, a radiant type fuelv burner in the upper end of said heating chamber above said virst named annular wall a iue communicating with thelower end of said heating chamber, and means in said heating chamber to prevent' short circuiting of the vheated gases and products of combustion.-

In testimony whereof, I have hereunto set my hand.

- ROBERT E. CRAMER.

enclosing side and top walls,

lar wall, said last named wall extending up- I wardly from a point adjacent the lower end of said first named annular wall to a point above said lirst named wall and being reversely bent I and secured to said rst named wall, a bottom 

